What is BIMI (Brand Indicators for Message Identification)? How to add a brand logo to your Emails?
About
With BIMI 1), a logo file should be displayed in the receiver inbox.
Even if a trademark certificate is not requested by BIMI, most email providers require one, making it difficult for small companies to implement it.
How does it work?
When all requirements pass, the email provider will look up a TXT record where the content starts with v=BIMI1. In this record, it will find:
- the logo
- and optionally a certificate for the brand/mark
Example
With a TTL equivalent of 1 hour, the value of the TXT record could be:
Logo Only
v=BIMI1;l=https://example.com/brand-logo.svg
With a Verified Mark Certificate (VMC)
A Verified Mark Certificate (VMC) is a proof that the logo has been validated.
You can add a verified mark certificate if you have requested one with the a attribute
v=BIMI1;l=l=https://example.com/brand-logo.svg;a=l=https://example.com/vmc-certificate.pem
The full record example value if the BIMI group reference is:
default._bimi.example.com in txt
"v=BIMI1; l=https://www.example.com/path/to/logo/example.svg; a=https://www.example.com/path/to/vmc/VMC.pem;"
Record
Attributes
A BIMI record has three attributes:
- v=bimi1 – the record declaration indicating that this is a BIMI record
- l=URL – the hosting location of the SVG image.
- a=URL – the hosting location of the VMC/Assertion record
On which domain is the BIMI record retrieved?
The BIMI record is retrieved from the domain identified within the DKIM domain (ied=) value.
Cascading
A single global BIMI Record at the apex domain (organization domain) will cascade down to other subdomains
Selector
BIMI supports selectors allowing the same domain to publish multiple but separate records.
It could be used to segment different logos.
The base selector is default.
The DNS name should look similar to this default._bimi.example.com
Requirements
DMARC
BIMI requires:
- messages to pass the DMARC check (ie to be authenticated)
- the DMARC values of:
- reject for the p policy attribute
- 100 for the pct percentage attribute
URL
The logo URL (ie referenced by the l=):
- should be in HTTPS
- can resolve to any domain and directory path. It does not need to match the domain where the BIMI logo is published.
Verified Mark Certificate (VMC)
The BIMI standard does not require your logo to be a registered trademark to get a VMC 3)
But most providers do.
- Gmail requires it
- Zone requires it
- …
See Get your Verified Mark Certificate (VMC)
Logo
The SVG file requirements are:
- SVG Tiny: 4):
- Format: SVG Tiny Portable/Secure (SVG Tiny PS)
- baseProfile attribute: tiny-ps
- version attribute: 1.2
- <title> element: Should reflect your organization name. There are no strict requirements for the title value.
- Don’t include:
- External links or references, other than to the specified XML namespaces
- Scripts, animations, or other interactive elements
- x= or y= attributes in the <svg> root element
Google guidelines for compatibility
- Centered in a square.
- On a solid color background. Transparent backgrounds might not display as expected.
- 96 x 96 pixels or larger. (Gmail doesn't support SVG files with smaller dimensions 5))
- A small file size (<32 KB)
- The <desc> (description) element, for accessibility.
Provider Support and Specific Documentation
The list of provider that supports BIMI can be found at this address: https://bimigroup.org/bimi-infographic/
- Fastmail: https://www.fastmail.help/hc/en-us